Chronic pain is a significant problem for many osteoarthritis patients. The applicant's research has shown that following a 10 week cognitive-behavioral group intervention designed to improve pain coping skills, osteoarthritic knee pain patients show significant improvements in pain and psychological disability compared to patients receiving arthritis education or standard care. Two studies are proposed to further this research. Study 1 seeks to determine whether the effects of pain coping skills training can be enhanced by adding an innovative spouse training intervention that features behavioral rehearsal, patient-spouse home and in vivo practice sessions, and strategies for maintaining frequent practice of coping skills. 120 osteoarthritic knee pain patients will be randomly assigned to three conditions: pain coping skills training alone, pain coping skills training plus spouse training, or an arthritis education control condition. The study: 1) will evaluate whether spouse training helps patients maintain gains in pain relief and reduces pain behavior, and 2) determine how changes in patients' perception of pain relate to long-term (6-12 mos.) improvements in pain and disability. If spouse training enhances pain coping skills training, future research could identify the spouse training techniques that contribute most to treatment effects. If changes in pain perception relate to long-term improvements in pain and disability, this information could be used to identify patients who are most likely to maintain gains following cognitive-behavioral treatment. Study 2 investigates the neurobiological mechanisms of pain coping strategies. Several lines of evidence suggest that pain coping strategies affect the perception of pain through activation of endogenous morphine-like substances. To test this possibility, the applicant will carry out a controlled laboratory study in normal subjects. Tolerance for ischemic pain will be assessed under two conditions: following infusion of naloxone-an opiate antagonist, and following saline infusion. Previous research has shown tolerance for ischemic pain decreases following naloxone infusion indicating that ischemic pain activates endogenous opioids. The proposed study seeks to determine the extent to which pain coping strategies predict changes in pain perception that occur following naloxone infusion. If Study 2 indicates that pain coping strategies mediate pain through opioid activation in normals, future studies could evaluate whether a similar mechanism mediates the effects of pain coping strategies in arthritis patients.